EP4679635A1 - Radio wave reflecting plate - Google Patents

Radio wave reflecting plate

Info

Publication number
EP4679635A1
EP4679635A1 EP24766703.3A EP24766703A EP4679635A1 EP 4679635 A1 EP4679635 A1 EP 4679635A1 EP 24766703 A EP24766703 A EP 24766703A EP 4679635 A1 EP4679635 A1 EP 4679635A1
Authority
EP
European Patent Office
Prior art keywords
inclined surface
flat surface
radio wave
respect
reflected
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP24766703.3A
Other languages
German (de)
English (en)
French (fr)
Inventor
Gensyu TO
Lifei ZHENG
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Alps Alpine Co Ltd
Original Assignee
Alps Alpine Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Alps Alpine Co Ltd filed Critical Alps Alpine Co Ltd
Publication of EP4679635A1 publication Critical patent/EP4679635A1/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q15/00—Devices for reflection, refraction, diffraction or polarisation of waves radiated from an antenna, e.g. quasi-optical devices
    • H01Q15/14—Reflecting surfaces; Equivalent structures
    • H01Q15/18—Reflecting surfaces; Equivalent structures comprising plurality of mutually inclined plane surfaces, e.g. corner reflector

Definitions

  • the present disclosure relates to a radio wave reflector.
  • the conventional corner reflector enables retroreflection in a wide range of incident angles by use of the recessed portion of square pyramid type.
  • the conventional reflector is used as a reflector in a radar system that detects a target by reflecting a radio wave and a plurality of corner reflectors are placed in a narrow space, reflected waves from corner reflector adjacent to each other are recursively reflected. This may lead to mistaken detection of the target.
  • an object of the present disclosure is to provide a radio wave reflector that enables radio waves to be reflected within a narrow angular range in a front direction.
  • a radio wave reflector includes a first flat surface that reflects a radio wave as well as a first inclined surface that is connected to at least part of the outer edges of the first flat surface, is inclined with respect to the first flat surface, and reflects a radio wave.
  • the area of the first flat surface and the area of the first inclined surface have a relationship in which the difference between the maximum value of the strengths of reflected waves from the first flat surface and the maximum value of the strengths of reflected waves from the first inclined surface is equal to or smaller than a predetermined value.
  • the first inclined surface is inclined with respect to the first flat surface so that an overlap is formed between an angular range in which the reflected wave from the first flat surface has a predetermined strength or higher and an angular range in which the reflected wave from the first inclined surface has the predetermined strength or higher.
  • radio wave reflector of the present disclosure An embodiment to which a radio wave reflector of the present disclosure is applied will be described below.
  • like members will be denoted by like reference characters and there is a case in which overlapping descriptions are omitted.
  • a direction (X direction) parallel to the X axis, a direction (Y direction) parallel to the Y axis, and a direction (Z direction) parallel to the Z axis are mutually orthogonal.
  • the XYZ coordinate system is an example of an orthogonal coordinate system. Viewing in an XY plane will refer to front view.
  • the length, bulkiness, thickness, and the like of each portion may be indicated by being exaggerated.
  • “parallel”, “right angles”, “orthogonal”, “horizontal”, “perpendicular” “above”, “below”, and other words will allow deviations to the extent that effects of the embodiment are not lost.
  • Fig. 1A and Fig. 1B are drawings indicating an example of the structure of a radio wave reflector 100 in an embodiment.
  • Fig. 1A is a front view
  • Fig. 1B is a drawing indicating an example of the structure at the cross section along line A-A in Fig. 1A .
  • the radio wave reflector 100 includes a base 101, a first flat surface 110, and a first inclined surface 120A.
  • the radio wave reflector 100 is a radio wave reflector that can reflect radio waves in a narrow angular range in the front direction by reflecting the radio waves at the first flat surface 110 and first inclined surface 120A.
  • the XYZ coordinate system will be defined so that the origin of the XYZ coordinate system is taken as the center of the first flat surface 110, the first flat surface 110 is parallel to an XY plane, and a normal passing through the center of the first flat surface 110 matches the Z axis. That is, the first flat surface 110 is included in an XY plane.
  • the front direction of the radio wave reflector 100 is the Z direction.
  • the front direction of the radio wave reflector 100 matches the extending direction of the normal of the first flat surface 110.
  • the front direction of the radio wave reflector 100 is defined by the extending direction of the normal of the first flat surface 110.
  • Fig. 1B is a cross section of the radio wave reflector 100 indicated in Fig. 1A , the cross section being obtained by cutting the radio wave reflector 100 along an XZ plane.
  • the narrow angular range in the front direction is a range defined by a narrow angle centered around the normal (Z axis) passing through the center of the first flat surface 110. More specifically, the narrow angular range in the front direction is a range defined by a narrow angle centered around the normal (Z axis) passing through the center of the first flat surface 110 in a plane (here, an XZ plane) that is parallel to a plane (here, an XZ plane) including a direction (here, the X direction) in which the first flat surface 110 and an adjacent inclined surface (here, the first inclined surface 120A) are connected together and also including the front direction (Z direction) and that includes the normal (Z axis) passing through the center of the first flat surface 110.
  • the narrow angular range is an angular range within ⁇ 10 degrees centered around the normal (Z direction), is more preferably an angular range within ⁇ 5 degrees centered around the normal (Z direction), and is further more preferably an angular range within ⁇ 3 degrees centered around the normal (Z direction).
  • the base 101 is a member having the first flat surface 110 and first inclined surface 120A, which are formed on the +Z-direction side.
  • the base 101 is a bent plate-like member common to the first flat surface 110 and first inclined surface 120A, as an example.
  • the base 101 is not limited to a bent plate-like member.
  • the base 101 may be a cabinet or the like in a box shape or the like.
  • the base 101 only needs to be a member for which the first flat surface 110 and first inclined surface 120A can be formed.
  • the base 101 may be such that portions at which the first flat surface 110 and first inclined surface 120A are formed are separately structured.
  • the base 101 can be manufactured from a resin, a metal, a glass, or the like, as an example. Since the first flat surface 110 and first inclined surface 120A, which are a surface of the base 101, need to be a surface of a conductor, if the base 101 is manufactured from a resin or a glass, it suffices for the first flat surface 110 and first inclined surface 120A to be structured with surfaces to which conductor plating has been applied.
  • the resin a resin such as an acrylic resin, a vinyl chloride resin, or a polyester-based resin, for example, can be used.
  • the metal aluminum or the like, for example, can be used.
  • the first flat surface 110 is a reflecting surface perpendicular to the front direction of the radio wave reflector 100. This is because the front direction of the radio wave reflector 100 is defined by the extending direction of the normal of the first flat surface 110.
  • the first flat surface 110 is a flat surface.
  • the first flat surface 110 is in a rectangular shape in front view, as an example. Of the reflecting surfaces of the radio wave reflector 100, the first flat surface 110 is only the one reflecting surface perpendicular to the front direction.
  • the length of the first flat surface 110 in the X direction is a 1 and its length in the Y direction is b 1 .
  • an angle ⁇ (degrees) with respect to the normal (Z axis) passing through the center of the first flat surface 110 will be defined as indicated in Fig. 1B .
  • the angle ⁇ is used to represent the reflection direction of a reflected wave in an XZ plane.
  • the angle ⁇ is such that the angle inclined from the +Z direction toward the +X-direction side in XZ plane view as indicated in Fig. 1B is represented as a positive angle and that an angle inclined from the +Z direction toward the side opposite to the angle ⁇ indicated in Fig. 1B , that is, toward the -X-direction side, in XZ plane view, is represented as a negative angle.
  • the first flat surface 110 is not limited to a rectangular shape.
  • the first flat surface 110 may have any of a polygonal shape, a circular shape, an elliptical shape, and the like.
  • the outer edges of the first flat surface 110 may have a shape equivalent to at least part of a polygonal shape, a circular shape, and an elliptical shape.
  • the first inclined surface 120A is a reflecting surface connected to a side that is one of the four sides of the first flat surface 110 and extends in the Y direction on the +X-direction side, the reflecting surface being structured as a flat surface inclined with respect to the first flat surface 110.
  • a length in the horizontal direction when the first inclined surface 120A is viewed from the extending direction of the normal n1 is a 2 (the length will be referred to below as the horizontal length for the first inclined surface 120A), and a length in the Y direction is b 2 .
  • the area of the first inclined surface 120A may differ from the area of the first flat surface 110, the difference between these areas is preferably small.
  • the horizontal length a 2 of the first inclined surface 120A is equal to the length a 1 of the first flat surface 110 in the X direction
  • the length b 2 of the first inclined surface 120A in the Y direction is equal to the length b 1 of the first flat surface 110 in the Y direction. Therefore, the area of the first inclined surface 120A is equal to the area of the first flat surface 110, as an example.
  • the first inclined surface 120A is inclined with respect to the first flat surface 110 so that a valley fold is formed on the boundary with the first flat surface 110, as indicated in Fig. 1B .
  • the first inclined surface 120A is positioned on the +X-direction side of the first flat surface 110 and is inclined so as to approach the Z axis on the + side.
  • the first inclined surface 120A is in a rectangular shape as an example. Its side extending in the Y direction on the -X-direction side is connected to the first flat surface 110.
  • the first inclined surface 120A is not limited to a rectangular shape.
  • the first inclined surface 120A may have any of a polygonal shape, a circular shape, an elliptical shape, and the like.
  • the first inclined surface 120A only needs to be inclined with respect to the first flat surface 110 in a state in which the first inclined surface 120A is connected to at least part of the outer edges of the first flat surface 110.
  • the first inclined surface 120A like this has the following relationship with the first flat surface 110.
  • the area of the first flat surface 110 and the area of the first inclined surface 120A have a relationship in which the difference between the maximum value of the strengths of reflected waves from the first flat surface 110 and the maximum value of the strengths of reflected waves from the first inclined surface 120A is equal to or smaller than a predetermined value.
  • the first inclined surface 120A is inclined with respect to the first flat surface 110 so that, in an angular distribution of reflected waves with respect to the normal passing through the center of the first flat surface 110, an overlap is formed between an angular range in which the reflected wave from the first flat surface 110 has a predetermined strength or higher and an angular range in which the reflected wave from the first inclined surface 120A has the predetermined strength or higher.
  • RCS Radar Cross Section
  • the unit of RCS is dBSm.
  • an angular distribution of reflected waves from the radio wave reflector 100 will be evaluated by using an angular distribution of reflected waves with respect to the normal passing through the center of the first flat surface 110.
  • RCS of the reflected wave from the first flat surface 110 in the front direction of the radio wave reflector 100 in a rectangular shape can be represented according to the following equation (1), by using the length a 1 of the first flat surface 110 in the X direction and its length b 1 in the Y direction.
  • ⁇ is the length of a radio wave in a free space.
  • RCS of the reflected wave from the first inclined surface 120A in the front direction of the radio wave reflector 100 can be represented according to the following equation (2), by using the horizontal length a 2 of the first inclined surface 120A and its length b 2 in the Y direction.
  • ⁇ is the length of a radio wave in a free space.
  • the Z' axis is an axis parallel to the Z axis.
  • the radio wave reflector 100 reflects the radio wave in a narrow angular range in the front direction
  • the angle ⁇ of the first inclined surface 120A with respect to the front direction of the radio wave reflector 100 is very small.
  • the absolute value of the angle ⁇ is about 0.5 degrees to about 5 degrees, as an example.
  • Fig. 1C is a drawing indicating an example of an angular distribution of reflected waves from the radio wave reflector 100.
  • the angular distribution, indicated in Fig. 1C , of reflected waves from the radio wave reflector 100 is an angular distribution of reflected waves with respect to the normal (Z axis) passing through the center of the first flat surface 110.
  • the angular distribution is results calculated in an electromagnetic field simulation. In the simulation, an angle formed between the normal n1 of the first inclined surface 120A and the Z axis was set to 3 degrees, as an example. Also, RCS was calculated for both the first flat surface 110 and the first inclined surface 120A by using equation (1), under the condition that the area of the first flat surface 110 and the area of the first inclined surface 120A are equal to each other, as an example.
  • the horizontal axis indicates the angle ⁇ (degrees) and the vertical axis indicates RCS (dBsm).
  • the angle ⁇ on the horizontal axis is such that an angle inclined from the +Z direction toward the +X-direction side in XZ plane view as indicated in Fig. 1B is a positive angle and the angle ⁇ inclined from the +Z direction toward the - X-direction side in XZ plane view is a negative angle.
  • FIG. 1C an example of an angular distribution of reflected waves is indicated in a case in which radio waves are incident on the radio wave reflector 100 from the -Z direction.
  • the dotted lines indicate an angular distribution of the strengths of reflected waves reflected at the first flat surface 110.
  • the dash-dot lines indicate an angular distribution of the strengths of reflected waves reflected at the first inclined surface 120A.
  • the solid lines indicate the total of the angular distributions of the dotted lines and dash-dot lines. That is, the solid lines indicate an angular distribution of the total strengths of reflected waves reflected at the first flat surface 110 and reflected waves reflected at the first inclined surface 120A.
  • the maximum value of RCS was obtained when the angle ⁇ was about -3 degrees. It can be considered that since the first inclined surface 120A is positioned on the +X-direction side of the first flat surface 110 and is inclined so as to approach the Z axis on the + side and more radio waves are thereby reflected toward the -X-direction side than in the +Z direction, the maximum value of RCS was obtained in a range in which the angle ⁇ was negative.
  • the maximum value of RCS for the first inclined surface 120A was about 7.4 dBsm.
  • the strength of the reflected wave from the first inclined surface 120A is lowered as the angle ⁇ deviates from about -3 degrees.
  • RCS was about 0 dBsm.
  • RCS was about 0 dBsm or less.
  • the maximum value of RCS was obtained in a range in which the angle ⁇ was from 0 degrees to about -3 degrees.
  • the maximum value of RCS was about 7.4 dBsm.
  • RCS was about 0 dBsm when the angle ⁇ was around about +2.3 degrees and around about -5.3 degrees. In an angular range in which the angle ⁇ was about +2.3 degrees or more and an angular range in which the angle ⁇ was about -5.3 degrees or less, RCS was about 0 dBsm or less.
  • the angle ⁇ formed between the normal n1 of the first inclined surface 120A and the Z axis is very small, the angular distribution of the total strengths of reflected waves in a narrow angular range including the front direction was made substantially flat and substantially even by making the areas of the first flat surface 110 and first inclined surface 120A equal to each other. From this, it could be confirmed that the difference between the areas of the first flat surface 110 and first inclined surface 120A is preferably small.
  • Fig. 1D is a drawing indicating an enlarged view of the range in Fig. 1C in which the angle ⁇ is within ⁇ 10 degrees and the range in Fig. 1C in which RCS is -10 dBsm or more.
  • the up-and-down horizontal axis indicates the angle ⁇ .
  • the first inclined surface 120A was inclined with respect to the first flat surface 110 so that an overlap is formed between an angular range from ⁇ 2 to ⁇ 3, in which the strength of the reflected wave from the first flat surface 110 becomes a half of the maximum value, and an angular range from ⁇ 1 to ⁇ 2, in which the strength of the reflected wave from the first inclined surface 120A becomes a half of the maximum value.
  • the angular range in which the strength of the reflected wave from the first flat surface 110 becomes a half of the maximum value is the angular range from ⁇ 2 to ⁇ 3, in which the strength of the reflected wave from the first flat surface 110 becomes a value (about 4.4 dBsm) that is 3 dB less than the maximum value.
  • the angular range in which the strength of the reflected wave from the first inclined surface 120A becomes a half of the maximum value (about 7.4 dBsm) is the angular range from ⁇ 1 to ⁇ 2, in which the strength of the reflected wave from the first inclined surface 120A becomes a value (about 4.4 dBsm) that is 3 dB less than the maximum value.
  • the first inclined surface 120A only needs to be inclined with respect to the first flat surface 110 so that, in the angular distribution of reflected waves with respect to the normal passing through the center of the first flat surface 110, an overlap is formed between the angular range in which the reflected wave from the first flat surface 110 has the predetermined strength or higher and the angular range in which the reflected wave from the first inclined surface 120A has the predetermined strength or higher. It is only necessary for the predetermined strength to be equal to or higher than the strength of the reflected wave at the valley described above.
  • Fig. 2A and Fig. 2B are drawings indicating an example of the structure of a radio wave reflector 100A in a first variation of the embodiment.
  • Fig. 2A is a front view
  • Fig. 2B is a drawing indicating an example of the structure at the cross section along line B-B in Fig. 2A .
  • the radio wave reflector 100A includes the base 101, the first flat surface 110, the first inclined surface 120A, and a second inclined surface 120B.
  • the radio wave reflector 100A in the first variation of the embodiment has a structure in which the second inclined surface 120B is added to the radio wave reflector 100 (see Fig. 1A and Fig. 1B ) in the embodiment.
  • the radio wave reflector 100A is a radio wave reflector that can reflect radio waves in a narrow angular range in the front direction by reflecting the radio waves at the first flat surface 110, first inclined surface 120A, and second inclined surface 120B.
  • the radio wave reflector 100A will be described below, focusing on the difference from the radio wave reflector 100.
  • the base 101 in the first variation of the embodiment is a member having the first flat surface 110, first inclined surface 120A, and second inclined 120B, which are formed on the +Z-direction side.
  • the base 101 is a bent plate-like member common to the first flat surface 110, first inclined surface 120A, and second inclined surface 120B, as an example.
  • the base 101 is not limited to a bent plate-like member.
  • the base 101 may be a cabinet or the like in a box shape or the like.
  • the base 101 only needs to be a member for which the first flat surface 110 and first inclined surface 120A can be formed.
  • the base 101 may be such that portions at which the first flat surface 110 and first inclined surface 120A are formed are separately structured.
  • the material of the base 101 is similar to the material of the base 101 indicated in Fig. 1A and 1B .
  • the second inclined surface 120B is positioned on a side opposite to the first inclined surface 120A with the first flat surface 110 interposed therebetween.
  • the second inclined surface 120B is a reflecting surface connected to a side that is one of the four sides of the first flat surface 110 and extends in the Y direction on the -X-direction side, the reflecting surface being structured as a flat surface inclined with respect to the first flat surface 110.
  • the area of the second inclined surface 120B may differ from the area of the first flat surface 110, the difference between these areas is preferably small.
  • the area of the second inclined surface 120B may differ from the area of the first inclined surface 120A, the difference between these areas is preferably small.
  • a horizontal length when the second inclined surface 120B is viewed from the extending direction of a normal n2 (the length will be referred to below as the horizontal length about the second inclined surface 120B) is equal to the length of the first flat surface 110 in the X direction, and is also equal to the horizontal length of the first inclined surface 120A.
  • the length of the second inclined surface 120B in the Y direction is equal to the length of the first flat surface 110 in the Y direction and is also equal to the length of the first inclined surface 120A in the Y direction. Therefore, the area of the second inclined surface 120B is equal to the areas of the first flat surface 110 and first inclined surface 120A, as an example.
  • the second inclined surface 120B is inclined with respect to the first flat surface 110 so that a valley fold is formed on the boundary with the first flat surface 110, as indicated in Fig. 2B .
  • the second inclined surface 120B is positioned on the -X-direction side of the first flat surface 110 and is inclined so as to approach the Z axis on the + side.
  • the angle of the second inclined surface 120B with respect to the first flat surface 110 may differ from the angle of the first inclined surface 120A with respect to the first flat surface 110, their inclination angles are preferably equal to each other from the viewpoint of symmetry.
  • the angles (inclination angles) of the second inclined surface 120B and first inclined surface 120A with respect to the first flat surface 110 are both an absolute value of ⁇ .
  • the second inclined surface 120B is in a rectangular shape as an example. Its side extending in the Y direction on the +X-direction side is connected to the first flat surface 110.
  • the second inclined surface 120B is not limited to a rectangular shape.
  • the second inclined surface 120B may have any of a polygonal shape, a circular shape, an elliptical shape, and the like.
  • the second inclined surface 120B only needs to be inclined with respect to the first flat surface 110 in a state in which the second inclined surface 120B is connected to at least part of the outer edges of the first flat surface 110.
  • it is most preferable for the areas of the second inclined surface 120B and first inclined surface 120A to be equal to each other and it is also most preferable for their angles with respect to the first flat surface 110 to be equal to each other.
  • the second inclined surface 120B like this has the following relationship with the first flat surface 110.
  • the area of the first flat surface 110 and the area of the second inclined surface 120B have a relationship in which the difference between the maximum value of the strengths of reflected waves from the first flat surface 110 and the maximum value of the strengths of reflected waves from the second inclined surface 120B is equal to or smaller than a predetermined value.
  • the second inclined surface 120B is inclined with respect to the first flat surface 110 so that an overlap is formed between the angular range in which the reflected wave from the first flat surface 110 has the predetermined strength or higher and the angular range in which the reflected wave from the second inclined surface 120B has the predetermined strength or higher. This is similar to the relationship between the first flat surface 110 and the first inclined surface 120A.
  • Fig. 2C is a drawing indicating an example of an angular distribution of reflected waves from the radio wave reflector 100A.
  • the angular distribution, indicated in Fig. 2C , of reflected waves from the radio wave reflector 100A is an angular distribution of reflected waves with respect to the normal (Z axis) passing through the center of the first flat surface 110.
  • the angular distribution is results calculated in an electromagnetic field simulation. In the simulation, an angle formed between the normal n1 of the first inclined surface 120A and the Z axis was set to an absolute value of 3 degrees and an angle formed between the normal n2 of the second inclined surface 120B and the Z axis was set to an absolute value of 3 degrees, as an example.
  • RCS was calculated by using equation (1) under the condition that the areas of the first flat surface 110, first inclined surface 120A, and second inclined surface 120B are equal to one another, as an example.
  • the horizontal axis indicates the angle ⁇ (degrees) and the vertical axis indicates RCS (dBsm).
  • the angle ⁇ on the horizontal axis is such that as indicated in Fig. 2B , the angle inclined from the +Z direction toward the +X-direction side in XZ plane view is a positive angle and the angle ⁇ inclined from the +Z direction toward the -X-direction side in XZ plane view is a negative angle.
  • FIG. 2C an example of an angular distribution of reflected waves is indicated in a case in which radio waves were incident on the radio wave reflector 100A from the -Z direction.
  • the dotted lines indicate an angular distribution of the strengths of reflected waves reflected at the first flat surface 110.
  • the dash-dot lines indicate an angular distribution of the strengths of reflected waves reflected at the first inclined surface 120A.
  • the dash-dot-dot lines indicate an angular distribution of the strengths of reflected waves reflected at the second inclined surface 120B.
  • the solid lines indicate the total of the angular distributions of the dotted lines, dash-dot lines, and dash-dot-dot lines. That is, the solid lines indicate an angular distribution of the total strengths of reflected waves reflected at the first flat surface 110, reflected waves reflected at the first inclined surface 120A, and reflected waves reflected at the second inclined surface 120B.
  • Fig. 2C the angular distribution (dotted lines) of the strengths of reflected waves reflected at the first flat surface 110 and the angular distribution (dash-dot lines) of the strengths of reflected waves reflected at the first inclined surface 120A are identical to the results indicated in Fig. 1C .
  • the angle ⁇ was about 3.5 degrees, the maximum value was obtained.
  • the maximum value of RCS for the second inclined surface 120B was substantially equal to the maximum values of the first flat surface 110 and first inclined surface 120A, that is, the maximum value was about 7.4 dBsm.
  • the maximum value of RCS was obtained in a range in which the angle ⁇ was from about -3 degrees to about +3 degrees.
  • a property was obtained such as the one linking the maximum value ( ⁇ ⁇ -3 degrees) of RCS of the reflected waves from the first inclined surface 120A and the maximum value ( ⁇ ⁇ +3 degrees) of RCS of the reflected waves from the second inclined surface 120B together in a flat form.
  • the maximum value of RCS was about 7.4 dBsm.
  • RCS was about 0 dBsm when the angle ⁇ was around about -5.5 degrees and around about +5.5 degrees. In an angular range in which the angle ⁇ was about -5.5 degrees or less and an angular range in which the angle ⁇ was about +5.5 degrees or more, RCS was about 0 dBsm or less.
  • the angle ⁇ formed between the normal of the first inclined surface 120A and the Z axis is very small, the angular distribution of the total strengths of reflected waves in a narrow angular range including the front direction was made substantially flat and substantially even by making the areas of the first flat surface 110, first inclined surface 120A, and second inclined surface 120B equal to one another. From this, it could be confirmed that the difference among the areas of the first flat surface 110, first inclined surface 120A, and second inclined surface 120B is preferably small.
  • the angular range in which the strength of the reflected wave from the second inclined surface 120B becomes a half of the maximum value is the angular range from ⁇ 3 to ⁇ 4, in which the strength of the reflected wave from the second inclined surface 120B becomes a value (about 4.4 dBsm) that is 3 dB less than the maximum value.
  • the second inclined surface 120B only needs to be inclined with respect to the first flat surface 110 so that, in the angular distribution of reflected waves with respect to the normal passing through the center of the first flat surface 110, an overlap is formed between the angular range in which the reflected wave from the first flat surface 110 has the predetermined strength or higher and the angular range in which the reflected wave from the second inclined surface 120B has the predetermined strength or higher. It is only necessary for the predetermined strength to be equal to or higher than the strength of the reflected wave at the valley described above. Similarly, this also holds for the relationship between the first flat surface 110 and the first inclined surface 120A described by using Fig. 1A to Fig. 1D .
  • the maximum values of the strengths of their respective reflected waves are equal to one another. It could be confirmed that to increase the strength of the total reflected waves in the vicinity of the front direction to a certain extent, the difference among the areas of the first flat surface 110, first inclined surface 120A, and second inclined surface 120B is preferably small.
  • the area of the first flat surface 110, the area of the first inclined surface 120A, and the area of the second inclined surface 120B preferably have a relationship in which the difference among the maximum value of the strengths of reflected waves from the first flat surface 110, the maximum value of the strengths of reflected waves from the first inclined surface 120A, and the maximum value of the strengths of reflected waves from the second inclined surface 120B is equal to or smaller than the predetermined value.
  • Fig. 2D is a drawing indicating another example of an angular distribution of reflected waves from the radio wave reflector 100A in the first variation of the embodiment.
  • the property in Fig. 2D was calculated in an electromagnetic field simulation, as in Fig. 2C .
  • the dotted lines indicate an angular distribution of the strengths of reflected waves reflected at the first flat surface 110
  • the dash-dot lines indicate an angular distribution of the strengths of reflected waves reflected at the first inclined surface 120A
  • the dash-dot-dot lines indicate an angular distribution of the strengths of reflected waves reflected at the second inclined surface 120B
  • the solid lines indicate an angular distribution of the total strengths of reflected waves reflected at the first flat surface 110, reflected waves reflected at the first inclined surface 120A, and reflected waves reflected at the second inclined surface 120B.
  • the areas of the first inclined surface 120A and second inclined surface 120B are larger than the area of the first flat surface 110. Also, since the maximum values of the strengths of reflected waves from the first inclined surface 120A and second inclined surface 120B are equal to each other, the areas of the first inclined surface 120A and second inclined surface 120B are equal to each other.
  • Fig. 3A is a drawing indicating an example of the structure of a radio wave reflector 100B in a second variation of the embodiment.
  • the radio wave reflector 100B has a structure in which the first inclined surface 120A to a fourth inclined surface 120D in a trapezoidal shape are provided along the outer edges (four sides) of the first flat surface 110, the outer edges being in a rectangular shape.
  • the base 101 has a different shape from the base 101 indicated in Fig. 1A, Fig. 1B , Fig. 2A and Fig. 2B .
  • the radio wave reflector 100B has a structure in which the first inclined surface 120A and second inclined surface 120B indicated in Fig. 2A and Fig. 2B are changed to a trapezoidal shape, the third inclined surface 120C in a trapezoidal shape is connected to an edge of the first flat surface 110 in the -Y direction, and the fourth inclined surface 120D in a trapezoidal shape is connected to an edge of the first flat surface 110 in the +Y direction.
  • the sides equivalent to the upper bases of the trapezoidal shapes are connected to the four sides of the first flat surface 110.
  • the cross section obtained by cutting the radio wave reflector 100B along an XZ plane passing through the center of the first flat surface 110 is similar to Fig. 2B , and the cross section obtained by cutting the radio wave reflector 100B along an XY plane passing through the center of the first flat surface 110 is such that the first inclined surface 120A and second inclined surface 120B in Fig. 2B are replaced with the third inclined surface 120C and fourth inclined surface 120D.
  • first inclined surface 120A, third inclined surface 120C, second inclined surface 120B, and fourth inclined surface 120D are in a trapezoidal shape and are placed in that order when viewed from the front direction, enclosing the four outer sides of the rectangular shape of the first flat surface 110, as an example.
  • first inclined surface 120A, third inclined surface 120C, second inclined surface 120B, and fourth inclined surface 120D are structured in a mortar shape or tapered shape without a clearance. Therefore, reflected waves from the first inclined surface 120A and second inclined surface 120B are symmetrically and more evenly combined together, and reflected waves from the third inclined surface 120C and fourth inclined surface 120D are symmetrically and more evenly combined together.
  • the radio wave reflector 100 by which, in a desired angular range (narrow angular range) in the front direction, symmetry in angular distributions on both an XY cross section and an XZ cross section is high and radio wave strengths are even.
  • the inclination angles of the first inclined surface 120A and second inclined surface 120B with respect to the first flat surface 110 may be equal to each other, and the inclination angles of the third inclined surface 120C and fourth inclined surface 120D with respect to the first flat surface 110 may be equal to each other, as an example. Also, the inclination angles of the first inclined surface 120A and third inclined surface 120C with respect to the first flat surface 110 may be equal to each other, as an example.
  • the inclination angles of the first inclined surface 120A and second inclined surface 120B with respect to the first flat surface 110 may be equal to each other, the inclination angles of the third inclined surface 120C and fourth inclined surface 120D with respect to the first flat surface 110 may be equal to each other, and the inclination angles of the first inclined surface 120A and third inclined surface 120C with respect to the first flat surface 110 may be different from each other, as an example.
  • the inclination angles of the first inclined surface 120A and second inclined surface 120B with respect to the first flat surface 110 do not need to be equal to each other.
  • the inclination angles of the third inclined surface 120C and fourth inclined surface 120D with respect to the first flat surface 110 do not need to be equal to each other.
  • inclination angles for the third inclined surface 120C and fourth inclined surface 120D with respect to the first flat surface 110, for example, it is possible to obtain a reflected wave strength distribution that includes the front direction and deviates toward the -Y-direction side or +Y-direction side with respect to the +Z direction in XY plane view.
  • first flat surface 110 first inclined surface 120A, second inclined surface 120B, third inclined surface 120C, and fourth inclined surface 120D may be equal to one another.
  • the total reflected wave strength of radio waves from the five reflection surfaces can be made even on both the XY cross section and the XZ cross section in a narrow angular direction including the front direction.
  • first inclined surface 120A may be inclined with respect to the first flat surface 110 so that an overlap is formed in an angular distribution of reflected waves with respect to the normal passing through the center of the first flat surface 110 between an angular range in which the strength of the reflected wave from the first flat surface 110 becomes a half of the maximum value and an angular range in which the strength of the reflected wave from the first inclined surface 120A becomes a half of the maximum value.
  • the second inclined surface 120B may be inclined with respect to the first flat surface 110 so that an overlap is formed in an angular distribution of reflected waves with respect to the normal passing through the center of the first flat surface 110 between an angular range in which the strength of the reflected wave from the first flat surface 110 becomes a half of the maximum value and an angular range in which the strength of the reflected wave from the second inclined surface 120B becomes a half of the maximum value.
  • the third inclined surface 120C may be inclined with respect to the first flat surface 110 so that an overlap is formed in an angular distribution of reflected waves with respect to the normal passing through the center of the first flat surface 110 between an angular range in which the strength of the reflected wave from the first flat surface 110 becomes a half of the maximum value and an angular range in which the strength of the reflected wave from the third inclined surface 120C becomes a half of the maximum value.
  • the fourth inclined surface 120D may be inclined with respect to the first flat surface 110 so that an overlap is formed in an angular distribution of reflected waves with respect to the normal passing through the center of the first flat surface 110 between an angular range in which the strength of the reflected wave from the first flat surface 110 becomes a half of the maximum value and an angular range in which the strength of the reflected wave from the fourth inclined surface 120D becomes a half of the maximum value.
  • the angular range in which the maximum value of the strengths of reflected waves is obtained can be further expanded.
  • the four corners of the first inclined surface 120A, third inclined surface 120C, second inclined surface 120B, and fourth inclined surface 120D may have been chamfered as indicated in Fig. 3B .
  • the meaning of the trapezoidal shapes of the first inclined surface 120A, third inclined surface 120C, second inclined surface 120B, and fourth inclined surface 120D includes a shape like this.
  • the structure of the radio wave reflector 100B may be such that any three of the first inclined surface 120A, third inclined surface 120C, second inclined surface 120B, and fourth inclined surface 120D are provided around the first flat surface 110.
  • Fig. 4A to Fig. 4D are drawings indicating examples of the structures of radio wave reflectors 100C1 to 100C4 in other variations of embodiment 1.
  • the base 101 is omitted and only the structure of reflected surfaces is indicated in front view.
  • the radio wave reflector 100C2 indicated in Fig. 4B has a structure in which the first flat surface 110, first inclined surface 120A, and second inclined surface 120B of the radio wave reflector 100A indicated in Fig. 2A are deformed to a hexagonal shape (polygonal shape).
  • a polygonal shape only needs to have three sides or more.
  • a rhombic shape or the like may be taken.
  • a shape like this may be taken in conformity with restrictions and the like on structures and the like around the place at which to attach the base 101.
  • the positions of the first inclined surface 120A and second inclined surface 120B with respect to the first flat surface 110 may be shifted in the Y direction.
  • the radio wave reflector 100C3 indicated in Fig. 4C has a structure in which the first flat surface 110 and first inclined surface 120A of the radio wave reflector 100 indicated in Fig. 1A are deformed to a triangular shape.
  • a shape like this may be taken in conformity with restrictions and the like on structures and the like around the place at which to attach the base 101.
  • the radio wave reflector 100C4 indicated in Fig. 4D has a structure in which the first flat surface 110, first inclined surface 120A, second inclined surface 120B, third inclined surface 120C, and fourth inclined surface 120D of the radio wave reflector 100B indicated in Fig. 3A are deformed to an elliptical shape.
  • the shapes of the first flat surface 110, first inclined surface 120A, second inclined surface 120B, third inclined surface 120C, and fourth inclined surface 120D may be a circular shape instead of an elliptical shape.
  • a shape like this may be taken in conformity with restrictions and the like on structures and the like around the place at which to attach the base 101.
  • the reflecting surface has an elliptical shape, a circular shape, and a polygonal shape having three sides or more
  • the outer edges of at least one of a plurality of reflecting surfaces may have a shape equivalent to at least part of a polygonal shape, a circular shape, and an elliptical shape. It is possible to provide the radio wave reflector 100 with a structure having a great deal of freedom, in conformity with various purposes, restrictions on the surroundings, and the like.
  • the first inclined surface 120A may be an inclined surface that encloses all outer edges of the first flat surface 110.
  • the first flat surface 110 may be in a circular shape or elliptical shape and the first inclined surface 120A may be in a mortar shape or tapered shape that encloses all outer edges of the first flat surface 110 in a circular shape or elliptical shape.
  • a shape like this may be taken in conformity with restrictions and the like on structures and the like around the place at which to attach the base 101. It is possible to provide the radio wave reflector 100 with a structure having a great deal of freedom, in conformity with various purposes, restrictions on the surroundings, and the like.
  • the radio wave reflector 100 includes the first flat surface 110 that reflects a radio wave as well as the first inclined surface 120A that is connected to at least part of the outer edges of the first flat surface 110, is inclined with respect to the first flat surface 110, and reflects a radio wave.
  • the area of the first flat surface 110 and the area of the first inclined surface 120A have a relationship in which the difference between the maximum value of the strengths of reflected waves from the first flat surface 110 and the maximum value of the strengths of reflected waves from the first inclined surface 120A is equal to or smaller than a predetermined value.
  • the first inclined surface 120A is inclined with respect to the first flat surface 110 so that an overlap is formed between an angular range in which the reflected wave from the first flat surface 110 has a predetermined strength or higher and an angular range in which the reflected wave from the first inclined surface 120A has the predetermined strength or higher.
  • the radio wave reflector 100 having a desired angular range (narrow angular range) in a front direction is obtained.
  • the radio wave reflector 100 that can reflect radio waves in a narrow angular range in the front direction.
  • the first flat surface 110 may be in a rectangular shape.
  • the radio wave reflector 100 that is easy to manufacture and can reflect radio waves in a narrow angular range in the front direction.
  • the first inclined surface 120A may be in a rectangular shape.
  • the radio wave reflector 100 that is easy to manufacture and can reflect radio waves in a narrow angular range in the front direction.
  • the radio wave reflector 100 may further include the second inclined surface 120B that is connected to at least part of the outer edges of the first flat surface 110, is inclined with respect to the first flat surface 110, and reflects a radio wave, the second inclined surface 120B being positioned on a side opposite to the first inclined surface 120A with the first flat surface 110 interposed therebetween.
  • the area of the first flat surface 110 and the area of the second inclined surface 120B may have a relationship in which the difference between the maximum value of the strengths of reflected waves from the first flat surface 110 and the maximum value of the strengths of reflected waves from the second inclined surface 120B is equal to or smaller than a predetermined value.
  • the second inclined surface 120B may be inclined with respect to the first flat surface 110 so that an overlap is formed between an angular range in which the reflected wave from the first flat surface 110 has the predetermined strength or higher and an angular range in which the reflected wave from the second inclined surface 120B has the predetermined strength or higher.
  • the radio wave reflector 100 that can reflect radio waves in a desired angular range (narrow angular range) in the front direction by combining reflected waves from the first flat surface 110, first inclined surface 120A, and second inclined surface 120B.
  • the inclination angles of the first inclined surface 120A and second inclined surface 120B with respect to the first flat surface 110 may be equal to each other.
  • reflected waves from the first flat surface 110, first inclined surface 120A, and second inclined surface 120B are combined together, reflected waves from the first inclined surface 120A and second inclined surface 120B are symmetrically and more evenly combined together. Therefore, it is possible to provide the radio wave reflector 100 by which symmetry is high in a desired angular range (narrow angular range) in the front direction and moreover radio wave strengths are even.
  • the areas of the first flat surface 110 and first inclined surface 120A may be equal to each other.
  • reflected waves from the first flat surface 110, first inclined surface 120A, and second inclined surface 120B are combined together, reflected waves from the first inclined surface 120A and second inclined surface 120B are symmetrically and more evenly combined together. Therefore, it is possible to provide the radio wave reflector 100 by which symmetry is high in a desired angular range (narrow angular range) in the front direction and moreover radio wave strengths are even.
  • the first inclined surface 120A may be inclined with respect to the first flat surface 110 so that an overlap is formed between an angular range in which the strength of the reflected wave from the first flat surface 110 becomes a half of the maximum value and an angular range in which the strength of the reflected wave from the first inclined surface 120A becomes a half of the maximum value.
  • the radio wave reflector 100 can make an angular distribution of the total strengths of reflected waves substantially flat and substantially even. Therefore, it is possible to provide the radio wave reflector 100 that features high symmetry and moreover even and flat radio wave strengths in a desired angular range (narrow angular range) in the front direction.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Aerials With Secondary Devices (AREA)
EP24766703.3A 2023-03-06 2024-01-24 Radio wave reflecting plate Pending EP4679635A1 (en)

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JP2023033934 2023-03-06
PCT/JP2024/002023 WO2024185328A1 (ja) 2023-03-06 2024-01-24 電波反射板

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6385504A (ja) 1986-09-29 1988-04-16 Reiko Co Ltd 熱線遮蔽性透明フイルム
JP2023033934A (ja) 2021-08-30 2023-03-13 ブラザー工業株式会社 印刷システム及び制御装置

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3749880B2 (ja) * 2002-06-13 2006-03-01 株式会社エヌ・ティ・ティ・ドコモ アンテナ装置
JP4247174B2 (ja) * 2004-10-01 2009-04-02 株式会社エヌ・ティ・ティ・ドコモ アンテナ装置

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6385504A (ja) 1986-09-29 1988-04-16 Reiko Co Ltd 熱線遮蔽性透明フイルム
JP2023033934A (ja) 2021-08-30 2023-03-13 ブラザー工業株式会社 印刷システム及び制御装置

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
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US20250379368A1 (en) 2025-12-11

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